Retinex-RAWMamba: Bridging Demosaicing and Denoising for Low-Light RAW Image Enhancement

TL;DR

This paper introduces RAWMamba, a novel method that integrates demosaicing and denoising for low-light RAW image enhancement, utilizing a Retinex-based decomposition to improve cross-domain raw to sRGB mapping.

Contribution

The paper proposes RAWMamba, a two-stage approach that effectively combines demosaicing and denoising with Retinex prior for enhanced low-light RAW image processing.

Findings

Achieves state-of-the-art results on SID and MCR datasets.

Effectively reduces color distortions in low-light conditions.

Improves cross-domain raw to sRGB mapping performance.

Abstract

Low-light image enhancement, particularly in cross-domain tasks such as mapping from the raw domain to the sRGB domain, remains a significant challenge. Many deep learning-based methods have been developed to address this issue and have shown promising results in recent years. However, single-stage methods, which attempt to unify the complex mapping across both domains, leading to limited denoising performance. In contrast, existing two-stage approaches typically overlook the characteristic of demosaicing within the Image Signal Processing (ISP) pipeline, leading to color distortions under varying lighting conditions, especially in low-light scenarios. To address these issues, we propose a novel Mamba-based method customized for low light RAW images, called RAWMamba, to effectively handle raw images with different CFAs. Furthermore, we introduce a Retinex Decomposition Module (RDM) grounded in Retinex prior, which decouples illumination from reflectance to facilitate more effective denoising and automatic non-linear exposure correction, reducing the effect of manual linear illumination enhancement. By bridging demosaicing and denoising, better enhancement for low light RAW images is achieved. Experimental evaluations conducted on public datasets SID and MCR demonstrate that our proposed RAWMamba achieves state-of-the-art performance on cross-domain mapping. The code is available at https://github.com/Cynicarlos/RetinexRawMamba.